SHIPPING BIN MODEL (Correctly Wired)

This is a 3-D replica of a battery-operated model used in FGIS gate testing classes. It shows the bottom of a shipping bin, with a slide gate to control the discharge of grain. Two virtual soybeans represent the grain in the shipping bin. Below the bin gate is a pair of slide gates which form a diversion point. Opening the "SHIP GATE" allows the soybeans to flow to the ship, and opening the "RETURN GATE" allows them to flow back to the elevator (house). This model is fully functional. The gates are operated by clicking on the buttons with the mouse.

The model incorporates the basic elements of a monitoring and control system:

Each gate has two LIMIT SWITCHES which act as input elements, telling the system whether the gate is closed (CL) or fully open (FO).

INDICATOR LIGHTS tell the operator the current state of the system. Indicator lights have mostly been replaced by ICONS on computer screens, so there is also an icon next to the model which shows the bin status and gate positions. The icon shows the gate positions both by moving the gate images and changing their color from red (closed) to green (open).

Note: While the model has indicator lights to show when the diverter gates are fully open, the icon does not distinguish between partially open and fully open for these gates. GIPSA does not require a fully-open indicator for most gates, because the grain goes to the same destination whether the gate is fully partially open. An exception is the shipping bin gate. GIPSA requires this gate to be pulled fully open to make sure the bin is completely emptied, so the icon shows the bin gate in yellow when it is partially open and green when it is fully open.

The controls are PUSHBUTTONS which let an operator tell the system to move gates or change the status of the shipping bin. The icon has buttons that also operate the gates and change the bin status. The current shipping bin status is displayed at the top of the bin.

The output elements are not shown, but in a real shipping bin MOTOR CONTROL RELAYS provide power to electric motors, which move the gates. Some elevators operate the gates with pneumatic cylinders instead of electric motors.

The logic element, also not shown, is a PERMISSIVE RELAY which forces the bin gate closed unless certain conditions are satisfied. When the bin is in HOLD status, the relay keeps the bin gate shut. When the bin is in SHIP status, the bin gate is forced closed if any grain can flow back to the house. When the bin is in REJECT status, the bin gate is forced closed if any grain can flow to the ship.

The monitoring and control system shown is properly wired. The indicator lights show the true positions of the gates, and the relay removes the gate's permission to open at the right times.

You can move this model around with the arrows below the model.

Next Page: Alternative Correct Indicator Wiring